=^^= Happy Halloween =^^=
That’s VEKTOR. :D
This is devolving into pictures of VEKTOR dev.
I’ve broken my rule about showing my work on the web three times in three days. Working on a prototype and getting some real production numbers. I-AM-EXCITE.
Workin’ some steel for last few days. Nothing is definite. In over my head. I can swim.
On the VEKTOR (dropping the “Mk II”) front: the near-final version is made out of 113 components. Selecting actual parts today. The first edition/run will be a through-hole design on good old green masked PCB with high quality, hand picked and placed components.
Gearing up to build an estimate.
At VEKTOR MK II rev 6 I have DC-coupled the input amplifier to the two internal clipping amplifiers which takes the clippers off of the virtual ground circuit. High-pitch oscillations have been eliminated. Clean and dirty input amplifiers are now separate and two levels of input-clipping (compression) have been added to the dirty end. The input amplifiers are now based on the OPA2134 while the high-gain clippers are based on the wide-swinging TLC2272. I was hoping to get away with a 5532 in there…doesn’t cut it…NEED the swing.
These are probably the final VEKTOR Mk II clippers and shapers. Some Schottky action. :D
I have a capture from my scope here that shows the output of the buffer transistor immediately after the clipping section on one of the VEKTOR Mk II channels. The blue trace is the input to the circuit being generated by my bass as a sustaining E on the 1st string with the tone turned down to emphasize that nice fundamental sine-wave. The yellow trace is the output of the not-starved buffer transistor on the symmetrical channel.
Here the is the same scenario (I am playing a lower note) but after the tone contour section in the same amplifier channel. You can see how the tone contour circuit distorts the signal as it emphasizes certain frequencies by bypassing others. Notice that the distorted output waveform shows a higher frequency content than the input waveform: this is a visual demonstration of clipping harmonics in an audio signal. It shows how hard transitions in signal voltage can introduce higher frequency information into the signal.
You can also clearly see the fundamental under those partial spikes. This particular distortion shape is tracked flawlessly by my 3Leaf Audio Octabvre. Concerning guitar and bass distortion, this is octave food.
I’m working on massaging the noise floor and fine tuning the gain steps. VEKTOR will never be totally quiet at high distortion ratios but I would like to minimize noise for gentle-effect usage on the left half of the ratio (blend) control. I’m also concerned about noisy power supplies.
Some major changes to the VEKTOR Mk II circuit topology in version 5 A (NO DISASSEMBLE! D:) and I was able to solve some of the issues I was having with loading and internal impedance. I also have the transistors clipping asymmetrically and nicely. And with THAT everything sort of came to life…so…WOOT. :D
I started a new fuzz circuit prototype on the big breadboard that combines diode clipping and transistor clipping on two independently voiced channels. The layout includes two parallel clipping amplifiers with buffered tone contours and a clean blend at the output. The amplifiers are op-amp based diode-limited high-gain pushing good ol’ bipolar transistors which are biased to clip asymmetrically for lots of synthy mid-range harmonics. The idea is to provide a textured fuzz source for driving octaves and bass synth chains for bass and lead tones. If it goes on the big breadboard then it’s pretty important around here.
All great things begin on graph paper. So does a lot of not-so-great things.